Structure for connecting braided coaxial cable and connector to realize low passive inter-modulation performance

Abstract

The invention relates to a structure for connecting a braided coaxial cable and a connector to realize a low passive inter-modulation performance. The braided coaxial cable is provided with an aluminum foil layer and a braided layer; the connector is provided with an external conductor of the connector; the aluminum foil layer is composed of single layer of aluminum foil; the aluminum foil layer, the braided layer and the external conductor of the connector are welded together through a low-temperature and lead-free aluminum solder; or the external conductor of the connector is connected between the aluminum foil layer and the braided layer in a pressing manner; and the external conductor of the connector is connected with a medium layer and the aluminum foil layer of the braided coaxial cable in a precise transition fit manner. Preferably, the thickness of the single layer of the aluminum foil is 20-25 microns, the low-temperature and lead-free aluminum solder is Sn98Cu2+Flux2.5, the welding is the 360-degree welding, the maximum magnitude of interference of the precise transition fit is 0.05 mm, the maximum clearance is 0.05 mm, and the pressed length is 8-14 mm. The structure provided by the invention is ingenious in design and simple in structure and can obtain low passive inter-modulation; and meanwhile, the cost is not increased and the application of braided cables is expanded, so that the structure is applicable to being popularized and applied in a large scale.

Description

technical field [0001] The invention relates to the technical field of radio frequency signal transmission, in particular to a connection structure between a coaxial cable and a connector, in particular to a connection structure between a braided coaxial cable and a connector that realizes low passive intermodulation performance. Background technique [0002] At present, for 50-ohm braided cable products, PIM (Passive Inter-Modulation Distortion, Passive Intermodulation Distortion) performance is a very sensitive topic, and it is rare to find any description or data from product manuals and websites in the market. [0003] Due to the inherent disadvantages of the outer conductor-braid layer and aluminum foil layer (PET / EAA bonded double-layer aluminum foil) of the 50-ohm braided coaxial cable used in the communication industry, between the outer conductor of the cable and the outer conductor of the RF connector It is not easy to get consistent contact of 360 degrees, which i...

AI Technical Summary

Problems solved by technology

The outer conductor of the coaxial cable of U.S. Patent No. 6,053,769 is made of a layer of metal film, which can be copper, aluminum, etc. The outer conductor of the coaxial cable is inserted into the outer conductor of the connector and welded, wherein the outer conductor is 5 μm and no Braiding layer, and clearly pointed out that there are inherent defects in this thin metal outer conductor structure: easy deformation, fracture and peeling, poor mechanical stability

However, although the connection structures of coaxial cables and connectors in all the above-mentioned patent documents have improved the PIM performance to a certain extent, the PIM performance is still poor

[0005] At present, braided cables and connector products with passive intermodulation (PIM) performance as the technical highlight have appeared in the industry, but they are basically built around the braided layer. The typical design is to remove the shielding layer of aluminum foil, and the braided Layer thickening and densification to increase the weaving density or increase the number of weaving layers. Generally, one layer of braiding layer is increased to two, three or even four layers to achieve the same shielding effect as the previous layer of aluminum foil plus one layer of braiding. Connectors The braided cable connection with this low PIM design includes soldering, clamping termination, etc., and the design principle of the cable connection mechanism of the existing connectors on the market is the same, nothing new

At the same time, due to the removal of aluminum foil, which is a unique shielding method of braided cables, and the increase of braiding density or the number of braiding layers, braided cables have no cost advantage compared with 360° all-copper or all-aluminum corrugated cables and smooth-walled cables. Performance is at a disadvantage, such as high frequency, high power microwave applications and high electromagnetic compatibility requirements (EMC) occasions, etc.

[0006] Due to the poor passive intermodulation (PIM) performance of traditional braided cables, the typical value of PIM is only -60~-80dBm, which seriously limits the application of braided cables in the field of wireless communication.

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